[media] Staging: media: bcm2048: warnings for uninitialized variables fixed

This patch fixes the following sparse warnings:
warning: ... may be used uninitialized in this function
Some function variables have been initialized to 0.

Signed-off-by: Andrew Milkovich <amilkovich@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>